A randomised double-blind placebo-controlled phase II trial of palbociclib combined with letrozole (L) in patients (pts) with oestrogen receptor-positive (ER+) advanced/recurrent endometrial cancer (EC): NSGO-PALEO/ENGOT-EN3 trial - Mirza, M; Bjørge, L; Marmé, F (Ann Oncol, 2020)